Seeking custody of children & filing defamation case on my wife.

Dear sir, We are married for 11 years from Nov 2004.My wife is a home maker.I am working as a professor.There have been frequent quarrels between us due to her ignorance about the family life and she often runs away with my two children to her mothers house disturbing my children psychologically & their studies.She has been a constant disturbance to me & my family from the marriage date.Her IQ is very poor.She is threatening me that she would kill my children .On 15th of august 2015 she quarreled with me & took away my children and registered false/Fraud/fake Information Report leading to 498a on me, my sister & my mother.We got AB.Now I want to file defamation case & take my children under my custody.They are 11 years & 9 years old.My wife has only mother & her father died when she was 8 years old.Her mother is totally uneducated & my wife is a psycho.I have not got even a single rupee as dowry.She has not spent any money for educating my children.I am spending rs 2.5 lakhs every year for both in a good CBSE school.I am very much worried about the childrens future.I feel that my wife would spoil thier life,education etc.I have paid this years full fees.But she went & stayed in her mothers house.I want an immediate solution to take custody of my children as they are missing school very much.Pl suggest me what to do.Shall I get stay?. Two options: 1) get stay & proceed to file case on my wife for defamation 2) Get stay & ask for childrens custody. I want this to be done quickly by court because delay may lead to my childrens academic break. FACTS MARRIAGE NOV 2004. BOY BABY BORN SEP 2005. From this day she broke her relationship with my mother,sister,father & all our relations. I used to visit her mother house from sep 2005 to june 2011 as she was staying there in mothers house. second girl child born on march 2008. she came with two children to my separate house on june 2011. during all festivals,week ends,national holidays,summer & winter vacation she runs away with my only for 180 working days of school she will be at home. I am working in bangalore.My house in salem.Her mothers house is 30 km from my house.I come during week ends to my house.As of now these are petty problems.but keeping this in mind she simply filed 498a. PL SUGGEST. Regards person in jeopardy.